Which is better for one person?

The bunch of 6. A 3 lb bag is roughly 10 to 14 bananas and often ripens faster than one person can eat them.

Neither keeps much longer than the other; both are fresh fruit. The bunch of 6 is easier to finish before it overripens, while bagged bananas are more likely to need freezing.

Is the 3 lb bag worth stepping up to?

Yes if you have a family or use bananas in smoothies and baking. Otherwise the smaller bunch gives you better control and less waste.

Can I freeze bananas from either?

Yes. Peel and slice or mash either one, then freeze. The bag suits this better because you can process a large batch at once.

Are they the same kind of banana?

Both are standard fresh dessert bananas, the common Cavendish type. The difference is packaging and quantity, not variety.

Bananas - Bunch of 6 vs Banana Bag 3 lbs

Buy the bunch of 6 if you want a small, fixed count you can eat through before it browns. Buy the 3 lb bag if you have a household that goes through bananas fast or you plan to freeze or bake with them. Both are plain fresh bananas with no meaningful build or feature difference; the real split is count versus weight, and the bag gives you more fruit with less control over ripeness per piece.

Choose the bunch of 6 if you want a set count for one or two people and prefer picking bananas you can see and feel.
Choose the 3 lb bag if you need a larger, pre-measured amount for a family, smoothies or baking and don't mind less say over individual ripeness.

Prices

Bananas - Bunch of 6: $4.10 at Water Butlers (last seen Nov 13)
Banana Bag 3 lbs: $1.79 at Pronto Home Delivery (last seen Nov 13)
Difference: the Banana Bag 3 lbs is $2.31 cheaper than the Bananas - Bunch of 6 at the latest prices (Nov 13)